These maneuvers are open to all warriors, and may be available to other classes as well, but the DM is free to require that other classes spend a proficiency slot to have access to these maneuvers.
To be able to make use of a maneuver the character must meet 2 requirements. First, he must roll a critical hit. Second, he must have the skill level with his weapon that the maneuver requires. All maneuvers are for melee use only, missile attacks do not present the opportunity to use these moves.
When a character rolls a critical hit, he can choose to take the critical result, or forfeit that critical result, including the double/triple damage, and use a maneuver instead. The decision is made after the critical roll, but before the critical result is rolled. If the maneuver is chosen, the attack still does normal damage in addition to the special maneuver effects(unless otherwise stated in the maneuver). The following are the most common maneuvers that all warriors would learn, but a warrior can create others, so long as they match the existing ones in the degree of their effect. This creation will also require the warrior to spend a character point. Then, only he could use the maneuver unless he taught it to others, who would also need to spend the character point to learn it.
-Maneuvers of Proficiency
Unarmed Attack: the attacker can make a free single unarmed attack. He must have a free hand to punch, otherwise, he can kick if proficient in doing so. This can even be a wrestling attack. The free unarmed attack does not provoke an attack of opportunity from the defender, since the attacker has opened up his defenses in such a way as to slip in this move. This unarmed attack must be made immediately, and can be any offensive unarmed move, not just a punch/kick. So the warrior could make an unarmed disarm, grab attack, pull/trip, etc.
Melee break: this allows the attacker to break from melee with the defender and take action as if the defender did not threaten him. If the attacker could normally have a chance to knock down his foe, then the attacker can force the defender to retreat 5 feet in addition to the melee break bonus.
Slash Attack: the attacker can cut/slash any single strap, rope, sack, pouch, candle, etc. in his melee reach without the defender having any chance to respond.
-Maneuvers of Specialization
Pummel Attack: the specialist can get a free pummel attack, and is able to use his weapon hilt/guard or any object he can grab(if he has a free hand) to attack with. This is just an upgrade of the free unarmed attack maneuver that proficient weapon users can choose. It also does not provoke any attack of opportunity from the defender.
-Maneuvers of Mastery
Viper Strike: this maneuver allows a weapon master to cover his target. The normal rule that the maneuver is in addition to normal damage does not hold here. The master forfeits his full attack, the one that rolled the critical hit, and is able to put his weapon at his foes throat, covering him as per normal covering rules. This only works with bladed weapons. The master can then menace the defender, and can drive the attack into the defender in any phase he wants, just as per normal cover rules. If the master rolls a critical hit on the actual cover attack roll, he can choose the location the critical hit affects. You can see how deadly such an attack can be! Such a move forces a morale check on the defender to see if he will ignore the threat and attack rather than surrender.
-Maneuvers of Grandmastery
Tumble: this move allows a grandmaster with tumbling skill to tumble around the defender and threaten his back. If the defender fails his surprise check, the grandmaster gets a free attack of opportunity against his back!
Double Move: this simply allows the grandmaster to perform any 2 lesser moves. They must be different moves, but any combination is possible. The unarmed attack and pummel attack are effectively the same move for this determination, since the pummel attack is just a better unarmed attack maneuver.
OTHER COMBAT MANEUVERS
These maneuvers can be performed by anyone. They do not require the opening(a critical hit) the above maneuvers require.
Give Ground: the defender can fall back away from the attacker and use the backward motion to defend himself. He must be able to safely move back to use this option. Defenders can gain up to a -2 AC bonus with this option(up to a -4 AC bonus if the defender has tumbling). For each -1 AC bonus he gains, he also gets a -1 to hit penalty, as he is not focused fully on attacking. If the attacker is man-sized or less, each -1 AC bonus gained requires the defender to retreat 1 HEX(5 feet). Every size above man-sized the attacker is requires an extra HEX per -1 AC bonus, so a huge giant requires a 3 HEX retreat per -1 AC bonus gained. A defender cannot retreat more than half his movement rate in this fashion.
Feint: this move is a combination called shot and strike. The attacker declares he is feinting, and declares the degree of this attempt, as a stated penalty to hit. His attack suffers this to hit penalty, but so does the parry/dodge attempt of the defender. An attacker can attempt a perception check to read his foe and determine if he is attempting to parry/dodge his attack. This will then allow him to declare the feint after he attacks, but before his die roll so he can better his odds at actually getting through the defense. This tactic only helps against foes who do not have a good AC, and rely on parrying/dodging to defend. It allows the attacker to use some of his skill(THAC0) to reduce the ability of his foe to defend.
Riposte: this move requires the defender to use an action to parry. His parry attempt is resolved at a -8 to hit, making this a difficult move for the unskilled. But, if he succeeds at his parry, not only does he foil the attack, but opens his foe up in such as way as to get an attack of opportunity! He turns his defensive move into an offensive opportunity. Those with martial arts Style D can attempt this with a dodge, rather than a block, in which case it is termed an Evade and Misdirect maneuver.
Martial Strike: this attack requires the user to learn the special vulnerable points on the body of his target. This requires that a proficiency slot be spent to gain this knowledge, and that martial arts Style A is also known. Each slot spent can give this knowledge for a small range of creatures. For reference, you can consider about 2 creature types who are similar in form to count as a small range for this purpose. So Humans and Elves could be taken for 1 slot, for example. If the race the target belongs to is understood in this way by the attacker, and he also has Style A, he can attempt this strike. He can use any weapon, and does not need to use an unarmed attack, but to do so, he must be at least a specialist in the weapon. The attack suffers the same penalty as a head shot(though it need not strike the head), -8 to hit and with the +3 initiative penalty, and gains the same bonuses, +2 AR and +2 to the knockdown roll. However, this move is superior to a standard head shot, in that all stun damage inflicted on the target is doubled(but this extra stun cannot exceed the base damage roll of the attack in any case). If a critical hit was also scored, then instead of this double stun effect, as it is already doubled by the critical anyway, the severity roll of the critical is increased by +2(up to the maximum result normally possible) or the targets save to avoid the critical is penalized by -2, the attacker has his choice.
Whirlwind Attack: this maneuver allows a combatant to attack as many foes he threatens as he wishes with a single attack. The outcome of this attack depends on how skilled the attacker is with his weapon.
Proficient: every extra target of the attack imposes a cumulative -2 to hit. So attacking 3 targets causes each to be attacked at -4 to hit. The attackers critical number is likewise reduced by 1 per extra target he attacks. The attacker makes a to hit roll against each target, then, he rolls for damage only 1 time. He divides this damage by the number of targets he attacked, regardless if he hit them all or not. Drop all fractions. This is how much damage each target takes that was hit.
Specialized: the attacker follows the rules for a proficient user, except his critical number is not reduced, and he only suffers a cumulative -1 to hit per target beyond the first.
Master: a master follows the rules for a specialist except he suffers no penalty to hit for attacking extra targets.
Grandmaster: a grandmaster follows the rules for the master, but he can choose to attack anyone within melee reach, even those not immediately threatened by him(like those to his flank or rear). A true whirlwind attack!